Question 1
The heart, muscles, bones, and blood develop primarily from
◦ ectoderm.
◦ mesoderm.
◦ endoderm.
◦ the placenta.
◦ the gray crescent.
Question 2
The hollow space within the blastocyst is the
◦ trophoblast.
◦ amnion.
◦ blastocoel.
◦ chorion.
◦ placenta.